Iatrogenic dissecting aneurysm of the internal carotid artery.

A secondary dissecting aneurysm after arterial injury has been reported as a complication of surgery. We encountered this phenomenon in a patient with a meningioma of the sphenoid ridge. Despite successful clipping of a small rupture in the anterior wall of the proximal portion of the internal carotid artery, the patient became drowsy 30 days after surgery and developed right hemiparesis followed by fatal bleeding from the internal carotid artery. Histological examination revealed a traumatic dissecting aneurysm which had developed from the tear in the intima and extended into the dural ring and the bifurcation of the carotid artery. The characteristic clinical and histopathologic findings are shown. Methods for early recognition and the possibility of immediate treatment are briefly discussed.